UNIVERSITY  OF   CALIFORNIA   PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


SELECTION  AND  TREATMENT  OF 

WATERS  FOR  SPRAYING  PURPOSES 

WITH   ESPECIAL   REFERENCE  TO 

SANTA  CLARA  VALLEY 


BY 
E.   R.  DEONG 


BULLETIN  No.  338 

December,  1921    . 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1921 


David  P.  Barrows,  President  of  the  University. 

EXPERIMENT  STATION  STAFF 

HEADS   OF  DIVISIONS 

Thomas  Forsyth  Hunt,  Dean. 

Edward  J.  Wickson,  Horticulture  (Emeritus). 

,  Director  of  Resident  Instruction. 

C.  M.  Haring,  Veterinary  Science,  Director  of  Agricultural  Experiment  Station. 

B.  H.  Crocheron,  Director  of  Agricultural  Extension. 
Hubert  E.  Van  Norman,  Dairy  Management. 

H.  J.  Webber,  Citriculture ;  Director  of  Citrus  Experiment  Station. 
William  A.  Setchell,  Botany. 
Myer  E.  Jaffa,  Nutrition. 
Ralph  E.  Smith,  Plant  Pathology. 
John  W.  Gilmore,  Agronomy. 
Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 
Frederic  T.  Bioletti,  Viticulture  and  Fruit  Products. 
Warren  T.  Clarke,  Agricultural  Extension. 
Ernest  B.  Babcock,  Genetics. 
Gordon  H.  True,  Animal  Husbandry. 
James  T.  Barrett,  Plant  Pathology. 
Walter  Mulford,  Forestry. 
Fritz  W.  Woll,  Animal  Nutrition. 
W.  P.  Kelley,  Agricultural  Chemistry. 
H.  J.  Quayle,  Entomology. 
Elwood  Mead,  Rural  Institutions. 
H.  S.  Reed,  Plant  Physiology. 
L.  D.  Batchelor,  Orchard  Management. 
J.  C.  Whitten,  Pomology. 
|Frank  Adams,  Irrigation  Investigations. 

C.  L.  Roadhouse,  Dairy  Industry. 
R.  L.  Adams,  Farm  Management. 

W.  B.  Herms,  Entomology  and  Parasitology. 

F.  L.  Griffin,  Agricultural  Education. 
John  E.  Dougherty,  Poultry  Husbandry. 

D.  R.  Hoagland,  Plant  Nutrition. 

G.  H.  Hart,  Veterinary  Science. 

L.  J.  Fletcher,  Agricultural  Engineering. 
Edwin  C.  Voorhies,  Assistant  to  the  Dean. 

division  of  entomology  and  parasitology 

W.  B.  Herms  S.  B.  Freeborn 

C.  W.  Woodworth  H.  H.  Severin 

E.  C.  Van  Dyke  E.  R.  deOng 

E.  O.  Essig  G.  A.  Coleman 


t  In  cooperation  with   Office  of  Public  Roads  and   Rural   Engineering,   U.   S. 
Department  of  Agriculture. 


SELECTION  AND  TREATMENT  OF  WATERS 
FOR  SPRAYING  PURPOSES  WITH  ESPECIAL 
REFERENCE   TO   SANTA  CLARA  VALLEY* 

By  E.  E.  deONG 

The  use  of  hard,  alkaline,  or  saline  waters  in  the  preparation  or 
dilution  of  sprays  and  dips  has  long  been  recognized  as  inadvisable, 
since  such  waters  may  seriously  reduce  the  efficiency  of  the  mixture 
or  may  produce  chemical  combinations  dangerous  to  vegetation  and 
animals :  ( 1 )  by  chemical  reactions  with  insecticidal  or  fungicidal 
materials,  which  neutralize  their  efficiency  or  form  dangerous  com- 
pounds ;  for  example,  the  use  of  alkaline  or  saline  water  with  acid 
(standard)  arsenate  of  lead  may  produce  a  soluble  arsenical  dangerous 
to  foliage;  (2)  by  physical  reactions,  such  as  the  breaking  of  oil  or 
cresol  emulsions  with  hard  water,  which  frees  the  chemicals  held  in 
suspension  and  destroys  the  value  of  the  mixture.  We  now  recognize 
such  dangerous  or  neutralizing  reactions  when  hard  and  perhaps 
alkaline  waters  are  combined  with  petroleum  or  cresol  emulsions,  acid 
lead  arsenate,  fish-oil  or  whale-oil  soap  and  nicotine  sulphate.1  The 
formation  of  a  precipitate  in  combining  lime-sulfur  solution  with  hard 
water  has  also  been  noted.  A  further  study  of  this  subject  may  reveal 
other  dangerous  or  undesirable  combinations. 

Defining  Alkaline  and  Hard  Waters. — Water  containing  consider- 
able-quantities of  soluble  sodium  salts,  including  chlorids,  sulphates, 
and  carbonates,  is  classified  as  "alkaline."  When  calcium  (lime)  or 
magnesium  is  present  in  considerable  proportion  either  in  the  bicar- 
bonate or  sulphate  form,  the  water  is  termed  "hard."  The  hardness 
of  water  is  of  two  types,  ' '  temporary ' '  and  ' '  permanent. ' '  The  first 
is  due  to  the  presence  of  bicarbonate  of  calcium  or  magnesium  held 
in  solution  in  the  water  by  an  excess  of  carbonic  acid.  This  type  may 
be  broken  up  by  boiling,  which  frees  the  carbonic  acid  and  throws 
the  calcium  out  of  the  solution  as  carbonate.  Permanent  hardness ' 
is  the  condition  resulting  from  the  presence  of  sulphates  or  chlorids 


*  The  author  wishes  to  acknowledge  the  valuable  assistance  received  in  this 
work  from  Mr.  George  P.  Gray,  Chief  of  the  Division  of  Chemistry,  State  Depart- 
ment of  Agriculture,  and  from  the  Division  of  Plant  Nutrition,  University  of 
California. 

i  Marion  Imes,  Cattle  Lice  and  How  to  Eradicate  Them.  U.  S.  D.  A.,  Farmers' 
Bull.  909,  p.  14,  1918. 


302  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

of  calcium  and  magnesium  and  of  the  carbonates  still  held  in  solution 
after  boiling.2  This  cannot  be  overcome  by  heating.  Both  types  can, 
however,  be  partially  counteracted  by  the  addition  of  caustic  soda, 
lye,  or  other  chemical  water  softeners.  In  this  bulletin,  no  distinction 
is  made  between  the  various  kinds  of  hardness,  whether  due  to  bicar- 
bonte,  sulphate  or  chlorid  of  calcium  and  magnesium,  as  their  reaction 
with  soap  is  somewhat  similar.  Neither  is  any  distinction  drawn 
between  temporary  and  permanent  hardness  of  water,  the  total  hard- 
ness alone  being  estimated. 

Plan  of  the  Survey. — As  waters  may  contain  dangerous  quantities 
of  salts,  a  survey  to  discover  something  of  the  degree  of  hardness 
and  the  distribution  of  such  waters  was  made  during  the  summer  of 
1919  in  the  Santa  Clara  Valley,  California,  a  typical  horticultural 
region,  supplied  with  moisture  principally  by  ground  water.  Here 
the  degree  of  hardness,  as  explained  later,  was  found  to  vary  from 
4  to  92  per  cent,  while  the  hardness  in  the  water  of  one  supply  com- 
pany increased  11  per  cent  from  the  first  of  May  until  the  middle 
of  August.  Complete  yearly  records  have  not  been  kept  but  we 
would  expect  that  the  concentration  of  salts  in  underground  water 
would  increase  during  a  long  continued,  arid  season,  such  as  is  com- 
mon in  California.  Samples  of  water  were  collected  from  the  entire 
valley  and  tested  by  means  of  a  standard  soap  solution.  A  knowledge 
of  the  comparative  quantity  of  salts  present  was  thus  obtained,  but 
it  was  not  possible  to  distinguish  between  the  kinds  of  salts,  as  their 
action  on  soap  is,  in  most  instances,  similar.  A  map  of  the  surveyed 
region  was  made  (see  Fig.  1,  page  304)  giving  the  location  of  each 
well  tested.  Surveys  of  this  nature,  giving  definite  information  about 
local  water  supplies,  will  enable  the  orchardist  to  choose  spray 
materials  suitable  to  his  water  supply.  The  manufacturer  of  insecti- 
cides will  find  this  information  of  value  in  preparing  and  marketing 
his  materials,  and  to  the  horticultural  officer  it  will  serve  as  a  guide 
for  his  recommendations  and  will  assist  in  explaining  orchard  troubles. 

Determination  of  Hardness. — The  soap-consuming  or  destroying 
power  of  a  sample  of  water  was  measured  by  means  of  a  standard 
soap  solution,  the  same  method  of  determination  being  used  throughout 
so  that  the  results  are  comparable.  The  soap  solution  used  was  pre- 
pared by  Prof.  P.  L.  Hibbard,  of  the  Division  of  Plant  Nutrition 
of  the  University  of  California,  and  contained  approximately  70 
parts  of  alcohol,  29  parts  of  water,  and  .4  per  cent  Ivory  soap.  The 
test  is  usually  made  by  measuring  out  50  c.c.  of  the  sample  of  water 

2  Standard  Methods  for  Examination  of  Waters  and  Sewage,  ed.  2  (1912), 
American  Public  Health  Association,  p.  32. 


BULLETIN  338]         TREATMENT   OF  WATERS  FOR  SPRAYING  PURPOSES         303 

into  a  stoppered  bottle  and  adding  measured  quantities  of  the  soap 
solution,  with  frequent  agitations,  until  a  stable  lather  is  formed 
which  remains  permanent  for  two  minutes.  The  samples  examined 
were  mostly  hard,  so  that  to  avoid  using  large  quantities  of  the 
standardized  soap  solution,  10  c.c.  of  the  sample  were  diluted  with 
40  c.c.  of  distilled  water.  The  soap  solution  was  then  added  in  small 
quantities,  shaken  vigorously  after  each  addition  until  a  permanent 
lather  was  secured  over  the  entire  surface  of  the  water,  with  the 
bottle  lying  flat  on  its  side.  The  number  of  cubic  centimeters  of  soap 
solution  thus  used,  multiplied  by  fifty  (when  10  c.c.  of  the  water 
sample  were  used)  gives  roughly  the  parts  per  million  of  calcium 
carbonate  or  equivalent  salts.  This  process  of  calculation  is  not 
entirely  accurate,  but,  since  comparative  results  are  wanted  and  not 
exact  analyses,  it  serves  the  purpose  of  this  investigation.  If  desired, 
a  more  accurate  estimate  of  the  degree  of  hardness  can  be  obtained 
by  checking  the  number  of  cubic  centimeters  of  soap  solution  used 
with  the  tables  found  in  standard  works  on  water  analysis.3 

Summary  of  Water  Tests. — A  condensed  record  of  all  the  tests 
made4  is  shown  in  Table  1.  The  column  at  the  left  indicates  the 
relative  degree  of  hardness  as  found  in  various  sets  of  samples.  For 
example,  4r-5  includes  all  the  samples  which  required  from  4.0  to  5.0 
cubic  centimeters  of  soap  to  give  a  permanent  lather.  The  column  of 
percentages  at  the  right  of  the  table  gives  the  proportion  in  which  this 
degree  of  hardness  was  present  in  the  total  of  all  tests  made. 

TABLE  1 

Summary  of  Hardness  Determinations  of  Santa  Clara  Valley  Waters 

Soap  solution  Proportion  in  amount 

used  of  total  tests 

Cubic  centimeters  Per  cent 

4-5 1.04 

5-6 11.96 

6-7 34.12 

7-8 36.27 

8-9 12.42 

9-10 2.30 

10  plus 1.89 


100.00 


3  Op.  tit.,  p.  33. 

*  Copies  of  the  detailed  reports  of  the  tests  made  in  the  Santa  Clara  Valley 
are  available  at  the  office  of  the  Director  of  Experiment  Station,  University  of 
California,  Berkeley,  the  Deciduous  Fruit  Station,  Mountain  View,  California 
and  the  office  of  the  County  Horticultural  Commissioner,  San  Jose.  As  an  aid 
in  identifying  the  samples,  the  name  of  the  owner  or  resident  of  the  property  from 
which  the  sample  was  taken  is  given,  together  with  the  district  in  which  it  is 
located,  and  the  name  of  the  nearest  road. 


304 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Assuming  that  six  and  less  denote  "soft"  water,  it  will  be  seen 
that  only  13  per  cent  of  the  total  tests  listed  in  Table  1  can  be 
placed  in  this  class.  If  those  of  a  slight  degree  of  hardness,  viz., 
6-7,  are  included,  the  total  still  falls  below  50  per  cent,  leaving  a 
remainder  of  53.83  per  cent  of  the  waters  classified  as  decidedly  hard. 
It  will  be  seen  from  the  map  that  the  districts  containing  the  most 
uniformly  soft  waters  are  located  at  the  extreme  northerly  and  south- 
erly ends,  viz.,  Agnew  and  Gilroy.  The  slightly  hard  waters,  with 
an    occasional    soft   well,    are    quite    evently   distributed    throughout 


Fig.   1. — Map  showing  location   and   degree   of  hardness   of  waters  tested. 


the  floor  of  the  vallej',  but  on  approaching  the  foothills,  the  degree 
of  hardness  usually  rises  rapidly,  as  shown  in  the  districts  of  Berry- 
essa,  Evergreen,  Morgan  Hill,  Almaden,  and  Los  Altos.  Considering 
the  valley  as  a  whole,  it  must  be  rated  as  a  region  of  hard  waters 
with  occasional  exceptions.  In  a  locality  where  hard  water  is  so 
thoroughly  distributed,  the  use  of  oil  emulsions,  as  commonly  made, 
must  be  and  is  attended  with  considerable  difficulty. 


WATER    SOFTENING 

The  removal  of  temporary  hardness  from  water  by  boiling  is  too 
ex  pensive  to  he  applied  in  preparing  sprays,  hence  we  must  depend 
on  chemical  water  softeners  to  reduce  both  the  temporary  and  perma- 
nent hardness  to  a  point  where  the  water  is  usable.     Such  chemicals 


BULLETIN  338]         TREATMENT   OF  WATERS  FOR  SPRAYING  PURPOSES         305 

may  have  different  functions  in  making  oil  emulsions,  viz.,  (1)  react- 
ing with  the  salts  in  the  water,  thus  reducing  the  soap-consuming 
power;  (2)  aiding  in  emulsif3dng  the  oil;  (3)  preventing  the  forma- 
tion of  insoluble  calcium  and  magnesium  soaps,  as  these  soaps  have 
a  tendency  to  clog  the  spray  nozzle. 

The  chemicals  tested  are  arranged  below  in  the  order  of  their 
merit,  with  regard  first,  to  economy  and  their  value  as  water  softeners. 

Caustic  Soda  (NaOH)  was  found  to  be  superior,  particularly  in 
very  hard  water,  to  all  other  chemicals  experimented  with  for  soften- 
ing water,  preliminary  to  emulsifying  either  crude  oil  or  distillates. 
The  caustic  soda  used  was  a  commercial  form,  95  per  cent  pure,  selling 
then  for  sixteen  cents  a  pound.  A  good  grade  of  caustic  soda  is  desir- 
able, although  the  presence  of  a  little  carbonate  of  soda  is  not  objec- 
tionable since  the  two  forms  precipitate  different  chemicals. 

Soda  Ash. — A  brand  of  washing  soda  known  as  the  "Wyandotte" 
is  the  common  water  softener  used  in  Santa  Clara  Valley.  This  chem- 
ical removes  the  calcium  carbonate  in  solution  in  the  water  but  does  not 
aid  in  emulsifying  the  oil  as  does  caustic  soda.  Its  value  was  less  than 
that  of  caustic  soda,  especially  in  very  hard  water. 

''Hydro  Pura"  and  "Rain-Water  Crystals"  are  two  commercial 
water  softeners  used  locally  for  laundry  purposes.  Analyses  of 
samples  by  the  Insecticidal5  and  Fungicidal  Laboratory  of  the  Univer- 
sity of  California  showed  them  to  be  mixtures  of  sodium  phosphate 
and  sodium  carbonate.  They  were  about  equal  in  value  and  ranked 
next  to  caustic  soda.  Their  high  cost,  however,  prevents  their  general 
use. 

Lye  of  commerce  is  usually  a  mixture  of  caustic  soda  and  carbonate 
of  soda.  This  would  seem  to  be  a  good  combination,  but  in  practice 
it  was  found  inferior  to  caustic  soda. 

Sal  Soda  (Na2CO3-10H2O)  is  the  crystallized  and  purified  product 
from  soda  ash.     Its  behavior  is  similar  to  the  crude  article,  soda  ash. 

Ammonia  has  also  been  found  of  value  with  some  waters  in  the 
making  of  emulsions. 

Use  of  Caustic  Soda. — The  value  of  caustic  soda  in  softening  waters 
whose  degree  of  hardness  ranged  from  7.2  to  9.1  is  shown  in  Table  2. 
The  data  given  here  may  serve  as  a  guide  in  determining  the  amount 
of  soda  to  use  per  100  gallons.  For  example,  1.6  pounds  of  caustic 
soda  (costing  25  cents)  per  100  gallons  of  water  reduced  by  40  per 
cent  the  amount  of  soap  necessary  to  emulsify  oil.  Later  it  will  be 
shown  that  from  one  to  two  pounds  of  caustic  soda  is  sufficient  to  give 
a  satisfactory  emulsion  with  most  waters  of  this  degree  of  hardness. 

s  Now  a  part  of  the  Division  of  Chemistry,  State  Department  of  Agriculture. 


306  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

For  many  soft  waters  one  half-pound  to  a  pound  of  caustic  soda  per 
100  gallons  was  sufficient. 

TABLE  2 

The  Value  of  Caustic  Soda  as  a  Water  Softener 
(Amounts  based  on  100  gallons  of  spray  mixture.) 


Can 

istic 

soda 

Reduction  of  soap  consumption 

Difference 

Amount 
Pounds 

Cost 

Amount*                   Cost 
Per  cent 

Loss  or  gainf 

1.6 

$0,256 

40                   $0.51 

$0.26  + 

3.2 

.51 

54                       .69 

.18+ 

6.4 

1.02 

59                       .75 

.27— 

*  The  amounts  in  this  table  were  figured  on  a  basis  of  eight  pounds  of  soap 
per  100  gallons.     Soap  and  soda  valued  at  16  cents  a  pound. 

f  The  results  from  the  use  of  caustic  soda  cannot  be  estimated  alone  by  the 
reduction  in  soap  consumption.  Its  value  as  an  aid  in  emulsifying  the  oil  is 
difficult  to  determine  but  must  be  considered. 

OIL    EMULSIONS    AND    HARD    WATER 

Petroleum  oil  is  usually  emulsified  by  the  use  of  fish  oil  or  laundry 
soap.  It  is  a  well  known  fact  that  the  use  of  hard  water  in  the  house- 
hold and  laundry  hinders  the  formation  of  lather.  Similarly,  hard 
water  destroys  oil  emulsions.  In  both  instances,  the  soluble  soda  and 
potash  soaps,  which  are  unaffected  chemically  by  soft  water,  react 
with  the  calcium  and  magnesium  salts  in  the  hard  water  and  form 
an  insoluble  soap  or  "curdle,"  as  it  is  sometimes  expressed.  This 
insoluble  soap  is  of  no  value  in  making  emulsions  or  to  increase  the 
cleansing  power  of  the  laundry  water  and  hence  is  a  waste.  There- 
fore, if  a  hard  water  is  used  in  preparing  or  diluting  an  emulsion,  the 
hardness  must  be  removed  by  the  use  of  a  preliminary  softening  agent 
or  by  sufficient  soap  to  produce  the  same  result.  A  slight  amount  of 
alkali  does  not  materially  retard  the  action  of  soap,  but  if  excessive 
quantities  of  sodium  salts  are  present  the  formation  of  lather  is 
checked. 

Oil  Emulsions  Made  with  Different  Types  of  Water. — The  vari- 
ations found  in  the  degree  of  water  hardness  require  a  corresponding 
adjustment  in  the  formulas  for  making  oil  sprays.  Trials  were  made 
with  a  number  of  waters,  to  secure  a  satisfactory  emulsion  with  a 
minimum  amount  of  soap  and  water  softener.  A  summary  of  these 
trials  is  shown  in  Table  3. 

The  amounts  of  water  softener  and  soap  given  are  averages  of 
trials  which  have  produced  satisfactory  emulsions  with  a  number  of 
waters  with  the  degrees  of  hardness  given  in  columns  1  and  6.  These 
figures  indicate  the  amounts  of  soap  and  softener  required  for  making 
emulsions  with  water  of  a  similar  type,  or  the  softener  alone  if  pre- 
pared emulsions  arc  used  which  are  not  adapted  to  hard  water. 


BULLETIN  338]         TREATMENT   OF   WATERS  FOR  SPRAYING  PURPOSES         307 


TABLE  3 

Summary  of  Modified  Formulas  for  Making  Oil  Emulsions   with 
Waters  of  Varying  Degrees  of  Haf.dness 

(Amounts  based  on  100  gallons  of  spray  mixture.) 


Crude  Oil 

Distillate  Oil 

Caustic  Soda 

Soda  Ash 

Caustic  Soda 

Soda  Ash 

Degree  of 
Hardness 

Amount 

of 

Caustic 

Soda 

Amount 

of 

Soap 

Amount 

of 

Soda 

Ash 

Amount 

of 

Soap 

Degree  of 
Hardness 

Amount 

of 

Caustic 

Soda 

Amount 

of 

Soap 

Amount 

of 

Soda 

Ash 

Amount 
of 

Soap 

c.  c. 
4-4.9 

pounds 

0.5 

0.66 

0.50 

0.8 
1.0 

1.+ 

pounds 

2.47 

4.83 

6.33 

6.83 

7.0 

7.0 

pounds 

1.5 
2.0 
2.2 

pounds 

6.0 
5.0 

7.8 

c.  c. 

5-5.9 

pounds 

0.75 

0.5+* 

1.5 

pounds 

5.5 
5.0 
5.0 

pounds 

3.0 
2.0 

pounds 

5.5 
5.0 

5-5.9 

6-6.9 

6-6.9 

9-9.9 

7-7.9 

8-8.9 

9-9.9 

*Only  one  test  was  made  with  distillate  on  account  of  a  scarcity  of  this  type  of  water.  The  figures 
given  are  the  exact  readings  while  the  other  amounts  in  the  table  are  averages.  This  amount  of 
variation  is  common  in  working  with  large  series  of  similar  types. 

Some  variation,  from  the  amounts  given,  will  of  course  be  necessary 
for  different  types  of  water  and  oil.  The  data  given  are  simply  the 
results  from  experiments  where  satisfactory  emulsions  were  secured, 
and  hence  may  be  taken  as  a  basis  from  which  to  work.  It  should 
be  remembered,  however,  that  changes  in  the  type  of  oil,  water,  or 
softener  used  mean  a  new  experiment,  and  should  be  considered  as 
such. 

TABLE  4 

Summary  of  the  Comparative  Emulsifying  Powers  of 
Laundry  and  Fish-Oil  Soaps 

(Amounts  based  on  100  gallons  of  spray  mixture.) 

Amount  of     Amount  of 
Soap  used  soap  soda  ash  Kerosene  Quality  of  emulsion 

Pounds  Pounds  Gallons 

Ivory  Soap 2  4  10  Satisfactory 

Crystal  White  3  4  10  Satisfactory 

White  Flyer  3  4  10  Satisfactory 

Ammonia  Borax  3  4  10  Satisfactory 

Octagon  Soap  Powder  ..3  4  10  Unsatisfactory 

Borax  Aid  3  4  10  Unsatisfactory 

Pearline  3  4  10  Unsatisfactory 

Light  House  Cleanser  ..3  4  10  Very  unsatisfactory 

Fish  oil*  5  3  10  Satisfactory 

*  A  semi-liquid  soap  containing  about  25  per  cent  more  moisture  than  a  hard 
soap. 


308  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

A  common  formula  for  making*  crude  oil  emulsion  with  moderately 
hard  waters  has  been  12  to  18  pounds  of  hard  soap  or  3  to  4%  gallons 
of  liquid  soap  per  200  gallon  tank,  with  soda  ash  as  the  water  softener. 
In  such  a  case,  it  would  be  well  to  try  substituting  caustic  soda  for 
soda  ash  and  to  use  25  to  50  per  cent  less  soap.  Where  prepared 
emulsions  are  used  with  soda  ash  in  hard  waters  a  change  in  the  type 
of  water  softener  might  be  found  desirable.  In  making  a  change 
from  a  well  established  custom,  it  is  always  well,  however,  to  try  the 
experiment  in  a  small  way  before  mixing  large  quantities. 

How  to  Use  the  Tables. — To  locate  the  nearest  water  that  has  been 
tested,  consult  the  map,  then  note  the  degree  of  hardness  given.  If 
no  tests  have  been  made  near  the  water  which  is  to  be  used,  or  if  from 
any  cause  conditions  seem  to  be  different,  then  a  simple  test  for  deter- 
mining the  hardness  may  be  made  as  described  on  page  312,  "Home 
Testing  of  Waters."  The  numbers  indicating  the  degree  of  hardness 
as  given  on  the  map  may  be  interpreted  as  follows : 

•  4  to  4.9 — very  soft 

5  to  5.9 — moderately  soft 

6  to  6.9 — slightly  hard 

7  to  7.9— hard 

8  to  8.9 — very  hard 

9  to  9.9 — extremely  hard 

For  very  hard  waters,  caustic  soda  will  probably  be  found  the  most 
satisfactory  as  a  water  softener ;  the  amount  to  be  used  may  be  deter- 
mined from  Table  3.  This  table  will  also  act  as  a  guide  to  the  amount 
of  soap  necessary.  To  illustrate :  If  the  waters  in  the  vicinity  of  the 
one  to  be  used  have  a  "degree  of  hardness"  of  7.5  to  8.5,  the  district 
is  apparently  one  of  hard  water.  Referring'  to  Table  3  for  a  suitable 
formula,  it  will  be  noted  that  the  waters  which  have  this  degree  of 
hardness  require  about  one  pound  of  caustic  soda  as  a  water  softener 
and  about  seven  pounds  of  hard  soap  to  make  a  satisfactory  crude 
oil  emulsion.  Make  an  experiment  with  a  small  amount  of  the  water 
and  oil  to  be  used,  in  the  proportions  suggested  in  the  table,  and  if 
a  satisfactory  emulsion  results  proceed  on  a  larger  scale.  Before 
making  emulsions  or  diluting  the  commercial  preparations  (which 
are  not  compatible  with  caustics),  wash  out  any  lime-sulfur  solution 
or  Bordeaux  mixture  that  may  be  in  the  tank.  Fill  the  latter  two- 
thirds  full  of  water,  add  the  water  softener,  and  allow  it  to  dissolve, 
then  add  the  dissolved  soap  and  finally  the  oil.  The  oil  should  be 
added  slowly  with  the  agitator  running. 


BULLETIN  338]         TREATMENT   OF   WATERS   FOR  SPRAYING  PURPOSES         309 


THE  RELATION  BETWEEN  ARSENICAL  INJURY  AND 
ALKALINE  AND  HARD  WATERS 

It  has  been  shown  in  recent  years  that  the  soluble  salts  commonly 
occurring  in  waters  (notably  sodium  chlorid,  carbonate,  and  sulphate) 
if  present  in  more  than  very  small  quantities,  may  exert  a  solvent 
action  on  acid  lead  arsenate.  Headden6  states  that  "he  considers  it 
unsafe  to  use  alkali  water  as  a  carrier  for  lead  arsenate"  and  cites 
experimental  data  where  sodium  sulphate  and  particularly  sodium 
chlorid  had  acted  as  a  solvent  for  lead  arsenate.  Haywood  and  Mc- 
Donnell7 report  experiment  data  as  follows : 

(1)  "Lead  arsenate  applied  with  spring  water  (containing  20 
parts  of  chlorin  per  million)  caused  some  injury  to  foliage.' 

(2)  "When  applied  with  distilled  water,  very  slight  injury 
occurred,  noticeably  less  than  when  the  spring  water  was  used.' 

(.3)  "When  applied  with  distilled  water,  to  which  10  grains  per 
gallon  (171  parts  per  million)  of  sodium  chlorid  had  been  added, 
rather  serious  injury  resulted.  When  distilled  water  containing  40 
grains  (684  parts  per  million)  of  sodium  chlorid  per  gallon  was  used, 
the  injury  was  very  much  increased,  practically  50  per  cent  of  the 
foliage  being  affected." 

(4)  "When  applied  with  distilled  water  containing  10  grains  of 
sodium  carbonate  per  gallon  (171  parts  per  million)  injury  was  notice- 
able fourteen  days  after  the  first  application,  and  seven  days  after  the 
third  application  the  trees  were  almost  completely  defoliated.' 

(5)  "Applied  with  distilled  water  containing  10  and  40  grains 
(171  and  684  parts  per  million)  of  sodium  sulphate  per  gallon,  some 
injury  resulted,  but  this  was  not  so  marked  as  that  produced  in  the 
presence  of  sodium  chlorid." 

From  the  above  data  it  will  be  seen  that  chlorin,  in  the  form  of 
sodium  chlorid,  is  especially  dangerous,  even  in  such  small  amounts 
as  twenty  parts  per  million,  and  this  element  is  very  common  in  Cali- 
fornia waters,  as  will  be  shown  later.  The  usual  reaction  between 
these  two  chemicals  is  the  formation  of  a  soluble  arsenate  and  a  com- 
plex lead  salt.  The  latter  may  be  disregarded  but  the  sodium  arsenate 
goes   into   solution   readily   in   atmospheric   moisture.      This   soluble 

6  Wm.  P.  Headden,  Arsenical  Poisoning  of  Fruit  Trees,  Colo.  Agr.  Exp.  Sta. 
Bull.  131,  p.  22,  1908. 

7  J.  K.  Hayvvood  and  C  O.  McDonnell,  Lead  Arsenate,  TJ.  S.  D.  A.,  Bur.  Chem. 
Bull.  131,  pp.  46-49,  1910. 


310 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


arsenic  is  then  absorbed  by  the  plant  and  causes  burning.  All  hard 
waters  do  not  necessarily  contain  chlorin  but  jnay  have  excessive  quan- 
tities as  shown  in  the  following  samples,  which  were  analyzed  by  the 
Division  of  Plant  Nutrition,  University  of  California,  the  results  being 
given  in  Table  5. 

TABLE  5 

Analyses  of  California  Waters 

Parts  per  million 

A ^ 


12  3 

Constituent                                                            Very  soft  Slightly  hard  Very  hard 

Calcium  (Ca)  40  50  25 

Magnesium   (Mg)   5  20  100 

Sodium  (Na)  32  52  384 

Bicarbonate    (HC03)    183  256  646 

Sulphate  (S04)  10  50  150 

Chlorin  (CI) 10  40  440 

Soap  Hardness  84  281  425 


Hypothetical  Combinations  of  Above  Analyses 

Parts  per  million 

A 


12  3 

Constituent  Very  soft  Slightly  hard  Very  hard 

Sodium  Sulphate   (Na2S04) 15  74  221 

Sodium  Chlorid   (NaCl) 33  66  726 

Sodium  Bicarbonate  (NaHC03)  51  17  109 

Calcium  Bicarbonate   (Ca(HC03)2)  160  200  100 

Magnesium  Bicarbonate   (Mg(HC03)2)  30  120  600 

The  degree  of  hardness  in  the  various  samples,  as  established  in 
this  survey,  is :  No.  1,  4.9  ;  No.  2,  6.7  ;  No,  3,  14.0.  It  will  be  noted  that 
the  chlorin  content  of  only  the  first  one  is  less  than  twenty  parts  per 
million — the  amount  which  was  associated  with  arsenical  injury  in 
Haywood  and  McDonnells  experiments.  As  already  mentioned,  one 
of  the  common  forms  in  which  chlorin  occurs  is  sodium  chlorid  (com- 
mon table  salt),  which  is  a  characteristic  component  of  saline  rather 
than  of  hard  waters.  A  study  of  the  analyses  of  California  waters, 
as  recorded  by  the  Division  of  Plant  Nutrition,  University  of  Cali- 
fornia, revealed  the  following  condition. 

If  20  parts  of  chlorin  per  million  be  taken  as  the  standard  and 
any  amounts  over  that  be  considered  as  possibly  dangerous  to  very 
susceptible  foliage,  then  of  80  analyses  which  this  laboratory  has  made 
of  California  waters,  we  have  the  following  proportions: 

14.8%  of  total  samples — safe  for  use  with  acid  arsenate  of  lead. 

12.1'/  of  total  samples — possibly  dangerous  on  tender  foliage. 

36.7%  of  total  samples — very  dangerous. 

36.4%  of  total  samples — extremely  dangerous. 


Bulletin  338]       treatment  of  waters  for  spraying  purposes       311 

These  samples  cannot  be  considered  as  entirely  typical,  since  there 
is  usually  some  suspicion  regarding  a  water  before  an  analysis  is 
requested.    They  do  show,  however,  the  presence  of  dangerous  waters 


Fig.    2. — Arsenical   injury   to   pear    foliage,    associated  Avith    the    use   of   acid 
arsenate  of  lead  in  hard  water. 

in  practically  every  part  of  the  State.  When  it  is  necessary,  in  the 
preparation  of  spray,  to  use  waters  that  are  at  all  hard  or  alkaline, 
the  best  plan  is  to  substitute  basic  arsenate  of  lead  for  the  acid  type, 


312  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

though  the  addition  of  milk  of  lime  or  a  quantity  of  lime  water  will 
usually  make  these  waters  safe  for  use  with  acid  arsenate  of  lead. 

PRACTICAL  APPLICATIONS 

The  use  of  hard  waters  in  spray  mixtures  is  a  serious  problem 
which  may  be  met  in  different  ways:  (1)  the  partial  softening  of  the 
water  by  means  of  chemicals;  (2)  location  of  a  source  of  soft  water 
within  hauling  distance  of  the  orchard;  (3)  impounding  of  surface 
waters  during  the  rainy  season;  (4)  installing  a  water-softening  plant; 
(5)  use  of  insecticides  or  fungicides  which  will  not  form  dangerous 
combinations  or  will  not  lose  their  efficiency  when  combined  with  hard 
water;   (6)  use  of  dusts  where  practical  instead  of  liquid  sprays. 

(1)  Water  softeners  (pp.  304-306)  may  be  economically  used  at 
a  cost  of  from  twenty  to  fifty  cents  per  hundred  gallons.  Caustic  soda 
has  given  the  best  results  in  these  experiments.  The  commercial  water 
softeners  "Hydro-Pura'?  and  "Rain-Water  Crystals'1  were  only 
slightly  inferior  to  caustic  soda  in  efficiency,  but  were  more  expensive. 
Soda  ash  may  be  used  in  fairly  soft  waters,  but  was  found  to  be  much 
inferior  to  caustic  soda  for  making  emulsions  with  hard  waters. 
These  materials  may  be  varied  in  refractory  cases  with  the  chance  of 
finding  a  form  particularly  adapted  to  certain  waters. 

(2)  Home  testing  of  waters  may  aid  in  locating  a  well  or  spring 
within  hauling  distance  of  the  orchard,  making  it  possible  to  avoid 
the  expense  and  annoyance  of  working  with  hard  waters.  For  such 
work  a  cubic  centimeter  graduate  is  desirable  but  if  not  available  then 
place  the  water  to  be  tested  in  a  two  quart  Mason  jar,  filling  it  just 
one-tenth  full.  Add  accurately  measured  quantities,  for  example  5 
cubic  centimeters  or  one  teaspoonful  of  any  soap  solution,  fasten  the 
top  securely,  and  agitate  for  ten  seconds.  A  lather  should  result  which 
will  last  for  two  minutes.  If  a  very  heavy  lather  results,  dilute  the 
stock  of  soap  solution  or  use  a  smaller  quantity.  If  the  lather  dis- 
appears too  quickly,  add  another  teaspoonful  of  the  original  soap 
solution.  By  using  uniform  quantities  of  the  waters  to  be  tested  and 
the  same  stock  solution  of  soap,  a  fairly  accurate  comparison  of  waters 
may  be  made  and  auy  marked  difference  in  the  degree  of  hardness 
determined.  If  desired,  standardized  soap  solutions  for  testing  waters 
may  be  obtained  from  most  chemical  houses. 

(3)  Surface  water  arising  from  rainfall  is  usually  softer  than 
water  from  springs  or  wells.  In  certain  localities,  it  may  be  possible 
to  impound  running  water  in  small  reservoirs  and  thus  secure  a  supply 
much  superior  to  underground  supplies.  In  many  places  in  Santa 
Clara  Valley,  water-  for  street  sprinkling  purposes  is  pumped  from 


BULLETIN"  338]         TREATMENT   OF  WATERS  FOR  SPRAYING  PURPOSES         313 

creeks  and  piped  long  distances.  This  supply  is  drawn  upon  by  the 
orchardists,  and  it  may  be  found  to  be  softer  than  their  well  water. 
In  the  interior  valleys  the  irrigation  canals,  fed  by  the  large  rivers, 
will  often  prove  a  source  of  decidedly  soft  water. 

(4)  Water-softening  plants  are  now  on  the  market  with  a  capacity 
suitable  to  the  needs  of  a  private  home.  The  cost  of  these  plants  will 
probably  range  from  a  few  hundred  dollars  up.  These  plants  handle 
two  or  three  thousand  gallons  or  more  in  twenty-four  hours  at  a 
moderate  cost  for  operation,  the  greatest  expense  being  that  of  in- 
stallation. When  rightly  equipped,  these  should  be  more  satisfactory 
than  attempting  to  soften  water  by  the  addition  of  strong  chemicals. 
This  method  will  give  soft  water  for  the  laundry  and  bath  as  well  as 
for  all  other  purposes,  a  factor  much  to  be  appreciated  in  the  home. 

(5)  Insecticides  and  fungicides  compatible  with  hard  water.  In 
many  instances,  standard  materials  may  be  found  which  can  be  used 
with  hard  waters  with  little  or  no  danger  of  neutralizing  their 
efficiency  or  of  forming  dangerous  compounds.  Where  this  can  be 
done,  it  offers  the  simplest  solution  of  the  problem.  Examples :  the  use 
of  basic  arsenate  of  lead  (approximately  one-fourth  arsenic  oxide) 
instead  of  the  standard  or  acid  type  (about  one-third  arsenic  oxide)  ; 
oil  emulsions  or  miscible  oils  which  are  made  especially  for  use  in  hard 
waters;  arsenical  dips  in  place  of  cresol  emulsions  (sheep  dip)  or  oil 
emulsions  made  by  means  of  soda  of  potash  soaps. 

(6)  Dusting  materials  instead  of  spray  mixtures,  where  practical, 
also  offer  a  convenient  means  of  avoiding  the  danger  from  hard  water. 
Much  has  been  said  recently  about  the  advantage  of  dusts  over  sprays 
in  the  economy  of  time  and  labor,  but  the  advantage  of  avoiding  the 
use  of  hard  or  alkaline  waters  has  apparently  been  overlooked. 

CONCLUSION    AND    SUMMARY 

Hard  water  forms  dangerous  combinations  with  or  destroys  the 
efficiency  of  many  forms  of  insecticides.  Such  waters  are  very  com- 
mon, especially  in  the  western  states.  Their  distribution  and  degree 
of  hardness,  however,  is  a  matter  of  only  approximate  knowledge. 

Danger  from  the  use  of  hard  water  comes  both  from  a  lack  of 
recognition  of  its  existence  and  from  the  imperfect  methods  of  over- 
coming the  difficulty  when  known. 

Softening  hard  waters  by  means  of  caustic  soda  or  other  water 
softeners  is  not  completely  successful  in  all  cases,  and  hauling  soft 
water  from  a  distance  in  quantities  sufficient  for  spray  purposes  is 
frequently   impracticable.      Surface   waters   are   usually   softer  than 


314  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

underground  supplies,  but  storage  of  the  former  during  rainy  seasons 
is  possible  only  in  limited  areas. 

Water-softening  plants  may  be  installed  at  a  cost  of  a  few  hundred 
dollars  with  a  sufficient  capacity  for  supplying  a  spraying  outfit  and 
also  meeting  the  domestic  needs  of  the  home.  Water  so  treated  is 
much  improved  for  baths,  laundry,  and  toilet  purposes. 

The  use  of  dusting  materials,  for  certain  cases,  in  place  of  liquid 
sprays,  offers  an  advantage  in  that  the  user  is  independent  of  the 
type  of  water. 

Insecticides,  compatible  with  the  soluble  salts  commonly  found  in 
waters,  are  desirable  and  may  be  a  satisfactory  solution  of  the  difficulty 
in  some  instances. 

Water  containing  chlorin  at  the  rate  of  20  parts  per  million  or 
more  has  been  reported  as  dangerous  to  use  with  acid  arsenate  of 
lead,  a  soluble  form  of  arsenate  being  formed  which  may  cause  severe 
foliage  injury.  Basic  arsenate  of  lead  should  be  substituted  for  the 
acid  type  if  used  with  very  hard  or  alkaline  waters. 

California  waters  have  an  unusually  high  chlorin  content,  which 
may  account  for  cases  of  arsenical  injury  that  have  occurred  where 
acid  arsenate  of  lead  has  been  used. 


